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OK you scientific types, answer me this one.
Posted: 30 December 2006 02:34 PM   [ Ignore ]
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Hubby and I were just watching the National Geographic Channel and learning about how the continents all came to be. 

Seems about 3 million years ago the Earth looked pretty much as it does today other than a few exceptions.  One of these was the Isthmus of Panama did not exist, and there was a a waterway between the North and South Americas.  This allowed a current to flow from the Pacific to the Atlantic and on up to what is now the ice cap area. 

Ok, here’s the kicker.  At that time there were no ice caps.  However, the warm water brought by the currents mixed with the colder water, which cause evaporation that came down in the form of rain and snow.  This, I gathered, created the ice caps. 

So, if the ice caps melt, will we all be under 200 feet of water as we have been told?  Or will we gain a few feet, lose the isthmus, gain back the currents to the ice cap area and start all over again. 

Sorry If I sound ignorant, but since I am, I might as well not try and deny it.  Besides the National Geographic Channel always creates more questions for me than it answers, and I guess that’s a good thing for my brain.  confused

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Posted: 30 December 2006 03:33 PM   [ Ignore ]   [ # 1 ]
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Hmmm, well I surely am NOT a scientific type but I would think that because the continents now above water have also been attacked by seismic activity all these billions of years.  There surely have been some ‘new’ alterations that would cause flooding to occur in places outside of what was lower ground in the beginning. 

For sure, California would become a group of islands?  Maybe parts of Florida and areas around the Gulf of Mexico would also go under and the Mediterranean would become more a part of the Atlantic?

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Posted: 30 December 2006 04:12 PM   [ Ignore ]   [ # 2 ]
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Bebelicious - 30 December 2006 07:34 PM

So, if the ice caps melt, will we all be under 200 feet of water as we have been told?  Or will we gain a few feet, lose the isthmus, gain back the currents to the ice cap area and start all over again.

I’m not entirely sure I understand what you’re asking, but I’ll give it a stab.  (I’ve never let my own ignorance stop me before!)

If you mean is a rise in sea level of a couple of feet a relatively minor thing, the answer is certainly not.  If the sea level rose even a few feet, it would be a global disaster.  If both ice caps completely melted, I suspect it would be the end of our civilization—and perhaps the end of humans.

If the film you saw implied that the change in currents (between N and S America) was the only thing that brought about the return of ice caps (and eventually glaciers in the temperate latitudes during the several ice ages), that’s a gross oversimplification.  Currents are important no doubt, but so are solar activity cycles, the change in the tilt of the Earth’s axis (precession), plate tectonics, and so on.  (I disremember the details but there have been several instances where ice dams held back massive amounts of water and caused instant, catastrophic changes when they failed.  This isn’t related to this thread—except to show that the global climate is very complicated—but mostly it’s just an amazingly cool thing.)

It sounds like you’re comparing that previous warm period with current global warming caused by human activity.  This is definitely a different story.

If global warming is caused by/leads to a run-away “greenhouse effect” (run away in the sense of positive feedback—the warmer it gets, the more carbon ends up in the atmosphere causing further warming), you can look at Venus as an example.

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Posted: 30 December 2006 05:18 PM   [ Ignore ]   [ # 3 ]
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The big factor in creating the intensified glacial cycles from about 2.5 million years ago onwards has been the uplift of the Tibet plateau (the creation of the Himalaya’s). This blocked N-S airflows in Asia, aided the build-up of a vast annual winter high over central Asia, and helped create the Asian monsoon pattern, thus influencing atmospheric circulation patterns in the whole northern hemisphere.

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Posted: 30 December 2006 06:51 PM   [ Ignore ]   [ # 4 ]
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I suppose I’m not really sure what I mean.  That’s my problem right there—- I’m completely confused.

HERE’S  the show in question in case anybody wants to watch it next time.  I’m sure it’s on several times this week.

I guess what I’m trying to say is that according to what I saw, there weren’t any ice caps 3 million years ago and if I remember correctly, that area was ocean and not land mass.  Florida and other areas that are today sea level were mostly sea level then as well.  Ocean and land looked relatively the same as they do today.  I’d always been taught the ice caps were over a land mass, but that didn’t seem to be the theory I watched today. 

Just hoping you guys out there know more than I do and I appreciate all the research and theories.

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Posted: 30 December 2006 07:18 PM   [ Ignore ]   [ # 5 ]
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There have apparently been ice caps on and off throughout the ages.  They’re around for a while, then they go away.  Most of the time there probably aren’t any, really, so they’re something of a novelty in that respect.  And sometimes there is land at the poles, and sometimes just water (or ice).  I think that the South Pole has been on Antarctica for at least the past 80 million years.  I’m not sure how long the North Pole has been water.

There are almost certainly many reasons for the creation of the ice caps, not just one or two.  The rise of the Tibetan Plateau almost certainly had a great impact on global climate, as LaMa said.  And the movement of the continents and ocean currents probably did things to the movement of cold and warm water towards the North and South Poles.  Then there are possible contributions from changes in the atmosphere.

As for what would happen if the ice caps melted. . .well, that’s going to call for a bit of speculation, especially as it partly depends on just what causes them to melt.  Obviously, global warming through atmospheric build-up of carbon dioxide would have different results than, say, the Earth plunging into the Sun.

If it’s a nice peaceful melting from a gradual warming of the planet’s overall climate, then the sea levels are certain to rise.  How much, I don’t know.  I do know that there is evidence in some places of sea levels being something like 60 meters higher than now (I remember that number from reading the reports of cave excavations at Gibraltar).  If that does happen, then it will change the outlines of the continents a lot.  Not quite on the level movies like Waterworld would have you believe, but still quite a bit.  Our friend LaMa in the Netherlands would need to be sure he could swim well, for one thing.  And perhaps we’d end up with the American Great Plains being a sea again.  I suppose you could get a topographical map of the world with elevations marked on it, and then start colouring in with blue all the sections open to the ocean that are below certain elevations to see what would stay and what would go.

Also, all that water melting would probably change the salinity levels of the ocean.  That would have effects on all sorts of things, from the water temperatures to what sorts of creatures lived in it.

Some things might change in other ways as well.  The weight of all that ice has pushed down places like Antarctica and Greenland.  Maybe with all that extra weight gone, they will rise back up again?

Whatever happens, we’re no doubt in for some changes over the next few thousand years.

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Posted: 30 December 2006 07:26 PM   [ Ignore ]   [ # 6 ]
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I just recently read an article in our local paper, which I can’t find but this is similar, which was saying that in the next century sea levels are expected to rise up to a metre and if this happens most of London will be underwater. They had a map of the city and showed which historical landmarks would be affected. There are also other low lying coastal cities that would be flooded too.

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Posted: 30 December 2006 07:33 PM   [ Ignore ]   [ # 7 ]
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At least it should be gradual for the most part, rather than people along the coast waking up one morning to see a giant wall of water rushing at them.  Inland areas would really be the ones in more danger, because the water could build up against hills or other landforms, and then suddenly break through in a rush.  It could be like the occasional floods in Holland, only potentially on a much larger scale (such as California’s Central Valley suddenly filling with water).

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Posted: 30 December 2006 08:34 PM   [ Ignore ]   [ # 8 ]
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At least Edinburgh’s pretty much well above sea level, except for parts like Leith, and its submersion might not be an entirely bad thing!  wink

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Posted: 30 December 2006 09:27 PM   [ Ignore ]   [ # 9 ]
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The truth is, no matter how much scientists theorize, and how many theories they publish as the “correct” theory, we will never be 100% sure until the time of the event actually arrives. Science is NOT an exact art. The gener theory is, “History repeats itself.” But what scientists say about the inside of the earth, the far reaches of our cosmos, the beginning and ends of time, black holes, the list goes on, is almost pure speculation. We dont know about the core of the earth because we havent BEEN there yet. We dont know about the edge of the universe because we havent BEEN there yet. And we dont know about the future of our earth because we are not there yet. The truth is, i dont know what is going to happen, and none of us will know for certain until it DOES happen.

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Posted: 31 December 2006 01:40 AM   [ Ignore ]   [ # 10 ]
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As to the ocean levels rising due to global warming.  What I’ve learned in my environmental science classes were that the problem isn’t the ice caps melting per se.  That would only raise the ocean level a bit.  The big problem is that if the earth is heating up, it raises the water temperature, causing the water to expand, raising the ocean level.  This amount is far more then just the ice caps melting.  So, that may explain why even when all the ice caps were melted in the earth’s history, the ocean levels weren’t “200 ft higher.”  That’s how I interpreted your question anyway.

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Posted: 31 December 2006 03:23 AM   [ Ignore ]   [ # 11 ]
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Melting of the Northpole and the sea-ice(!) of the Southpole will not rise the sealevels. You can test this. Take a glass, put a icecube in it and fill it to the rim with water. Now wait and let the ice melt. You will see that after the ice has melted the glass did not overflow.
The Northpole is one big floating piece of ice and is allready in the water. The problem of rising levels lies in the land ice. That is the mass of ice ON TOP of the continent of Antarctica.
Another test.
Same glass and setup as before, but now we make some landice in the form of a coffeefilter suspended above the glass filled with an icecube.
Let it all melt.
The icecube in the glass did nothing for raising levels, however as the “landice” in the coffeefilter melts ... the glass overflows.
Elementary.

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